Cam grinding apparatus



Nov. 15, 1955 Filed Jan. 14, 1953 J. W. NAREL CAM GRINDING APPARATUS 5 Sheets-Sheet 1 INVENTOR. J05EPH PV- NAR'EL BY W LAW A 7- TOENEY Nov. 15, 1955 J. w. NAREL 2,723,500

CAM GRINDING APPARATUS Filed Jan. 14, 1953 3 Sheets-Sheet 2 R. 4L (JOSEPH W NAREL Rig 3 vacuum ATTORNEY NOV. 15, 1955 w, NAREL 2,723,500

CAM GRINDING APPARATUS Filed Jan. 14, 1955 3 Sheets-Sheet 3 Fig 7 Egg F2 1. 6

fig/0 /5 I 4/12 l3 l6 1 47 49 Z7 Z6 Z5 Z 28- 36, 46 W 35 INVENTOR. JOSEPH W. NAE'EL WD.J6A

flTTaRA EY United States Patent 2,723,500 CAM GRINDING APPARATUS Joseph W. Narel, Worcester, Mass, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application January 14, 1953, Serial No. 331,190 6 Claims. (Cl. 51-101) The invention relates to grinding machines, and more particularly to a machine for grinding cam contours.

One object of the invention is to provide a simple and thoroughly practical grinding machine for grinding cam contours differing from end to end. Another object of the invention is to provide a cam grinding machine for grinding cam contours differing uniformly from end to end. Another object is to provide a cam grinding apparatus in which the head stock and foot stock are independently oscillated. Another object is to provide independent pivotally mounted head and foot stocks each of which is controlled by a separate master cam and a follower. A further object is to provide independent master cams andfollowers for imparting an oscillating movement to opposite ends of a work piece so as to generate a camcontour dilfering uniformly from end to end. Other objects will be in part obvious or in part pointed out hereinafter.

One embodiment of the invention has been illustrated in the drawings, in which:

Fig. l is a front elevation of a grinding machine embodying the invention;

Fig. 2 is a fragmentary plane view, on an enlarged scale, of the work supporting and actuating mechanism;

Fig. 3 is a fragmentary verticalsection, on a reduced scale, taken approximately on the line 33 of Fig. 2;

Fig. 4 is a fragmentary vertical sectional view, on an enlarged scale, taken approximately on the line 44 of Fig. 3;

Fig. 5 is a diagrammatic perspective view, on an enlarged scale of the portion of one of the work pieces, as positioned in the work holder of Fig. 2;

Fig. 6 is a similarly diagrammatic perspective view, on an enlarged scale of the other bladepositioned on the work holder of Fig. 2;

Fig. 7 shows diagrammatically the contour of the blades as seen from the left in Figs. 5 and 6; t

Fig. 8 shows diagrammatically the contour of blades as seen from the right in Figs. 5 and 6;

Fig. 9 is a transverse vertical sectional view, on an enlarged scale, takenapproximately on the line 9-9 of Fig. 1;and 4 t Fig. 10 is an elevation of one of the work pieces to be ground.

A grinding machine has been illustrated in the drawings comprising a base 10 which serves as a' support for a longitudinally movable work table 11. The work table 11 is arranged to slide longitudinally relative to the base 10 on a flat-way 12 and a V-way 13 formed on the upper surface of the base 10. A traversing mechanism is provided for traversing the table 11 longitudinally comprising a manually operable traverse wheel 14 which is connected through a gear and rack mechanism (not shown) such as is old and well known in the art.

The base 10 also, supports a transversely movable wheel slide 15 whichis arranged to slide transversely relative to the base 10 on a V-Way and flat-way (not shown). The wheel slide 15 supports a rotatable wheel spindle the 2,723,500 Patented Nov. 15, 1955 16 having a grinding wheel 17 mounted on the left hand end thereof, Fig. l).

A suitable driving mechanism is provided for the wheel spindle 16 comprising a motor 18 mounted on the upper surface of the wheel side 15. The motor is provided with an armature shaft 19 having a multiple V-groove pulley 20 mounted thereon. The pulley 20 is connected by multiple V-belts 21 with a multiple V-groove pulley 22 mounted on the right hand end of the wheel spindle 16.

A wheel feeding mechanism is provided for imparting a transverse feeding movement to the wheel slide 15 and the grinding wheel 17. This mechanism may comprise a half-nut 24 depending from the underside of the wheel slide 15. The half-nut 24 meshes with or engages a rotatable feed screw 25. The left hand end of the feed screw 25 is slidably keyed within a rotatable sleeve 26. The sleeve 26 is journalled in anti-friction bearings 27 supported by the base 10. The right hand end of the feed screw 25 (Fig. 9) is journalled in an anti-friction bearing 28 carried by a slidably mounted sleeve 29.

A hydraulically operated mechanism is provided for imparting a rapid approach'and receding movement to the wheel slide 15 comprising a cylinder 30 arranged in axial alignment with the feed screw 25. The cylinder 30 contains a slidably mounted piston 31 which is connected to the right hand end of a piston rod 32. The left hand end of the piston rod 32 is operatively connected to the sleeve 29.

A feed control valve 35 is provided for controlling the admission to and exhaust of fluid from the cylinder 30. This valve is a piston type valve which is normally held in a right hand end position by a compression spring 36. A solenoid S1 is provided which when energized serves to shift the valve 35 into a left hand end position. The hydraulic feed mechanism above described may be identical with that shown in the prior U. S. Patent No. 2,522,485 to H. A. Silven and C. G. Flygare dated September 12, 1950, to which reference may be had for details of disclosure not contained herein. When the solenoid S1 is energized, fluid under pressure is passed through a cylinder chamber formed at the right hand end of the cylinder 30 to move the piston 31 together with the wheel slide 15 and grinding wheel 17 toward the left so as to cause a rapid approaching movement of the wheel 17 toward the work piece to be ground.

A manually operable mechanism is provided for actuating the feed screw 25 comprising a manually operable feed wheel 40 mounted on the front of the machine base 10. The feed wheel 40 is arranged to rotate a gear 41 which meshes with a gear 42 mounted on the left hand end of a rotatable shaft 43. The right hand end of the shaft 43 is slidably keyed within the sleeve 26. It will be readily apparent from the foregoing disclosure that a rotary motion of the feed wheel 40 will be imparted through the mechanism just described to rotate the feed screw 25 so as to cause a transverse movement of the wheel slide 15. The direction of rotation of the feed wheel 40 determines the direction of the movement of the wheel slide 15 and the grinding wheel 17.

It is desirable to provide a power operated feeding mechanism to impart a grinding feed to the wheel slide 15. A fluid pressure operated feeding mechanism is provided comprising a cylinder 45 having a slidably mounted piston 46 contained therein. A rack 47 is formed in the upper face of the piston 46 which meshes with a gear 48 carried by a rotatable shaft 49. The shaft 49 is also provided with a gear 50 which meshes with the gear 42. It will be readily apparent from the foregoing disclosure that a longitudinal movement of the piston -46 will be imparted through the gear above described to transmit a rotary motion to the feed screw 25 so as to advance the wheel slide 15 and the grinding wheel 17 at a normal tween each and the intermediate shaft.

grinding'rate of speed. This grinding feed mechanism is substantially identical with that shownin the priorU. S.

Patent No. 2,522,485, above referred to, to which reference may be had for details of disclosure not contained herein.

The work table 11 serves as a support forarock bar 60. The rock bar is provided with .a' trunnion 61 which is supported in a bearing 62 fixedly mounted on the table The other end of the rockbar 60 is'provided with a relatively long trunnion 63 which is supported in spaced bearings 64 and. 65 which are fixedly-mounted within a housing 66 fixedly supported on the'work table 11. A foot stock 67 is adjustably mounted on the rock bar 60 and is provided with a foot stock center 68-for supporting the right hand end of the work-arborto be hereinafter described.

A head stock 70 is pivotally supported on the trunnion shaft 63 by means'of a pair of-spaced bearings 71 and-72. The head stock 70 is provided with a rotatable head stock spindlewhich is journalled in a bearing 74 carried by the head stock 70. The spindle 73 is provided with a driving plate 75 and a head stock center 76. The driving plate 75-is also providedwith a work driving pin 77.

A rock arm is keyed onto the trunnion shaft 63 so that the rock arm is arranged to transmit a rocking motion to the rock bar 60. The rock arm 80 is provided with a rotatable drive shaft 81 which is journalled in a bearing 82. A master cam 83 is mounted adjacent to the right hand end of the shaft 81. The shaft 81-is connected by a universal coupling 84 with a shaft 85. The shaft 85 is connected by a universal coupling 86 with the head stock spindle 73. The universal couplings 84 and 86 may be of any suitable or known construction and interrelationship to maintain identity or constancy of the angular'velocities of the driving and driven shafts even though displacements therebetween effect angularities be- The head stock spindle 73 is also provided with a master cam 87.

A rotatable shaft 90 is supported in a pair of spaced bearings 91 and 92 formed within the housing 66. A pair of spaced follower rollers 93 and 94 are mounted on the shaft 90 and positioned to operatively engage the master earns 83 and 87 respectively.

A tension spring 95 is connected-between a stud 96 anchored to the housing 66 and a stud 97- fixedly mounted on the rock arm 80. It will be readily apparent from the foregoing that rotary motion of cam 83 in engagement withthe follower roller 93, will impart a rocking motion to the rock arm 80 which in turn impartsa rocking motion through the trunnion shaft 63 to the rock bar 60. A tension spring 98 is connected at one end by a stud 99 with the housing 66. The other end of the spring-98 is connected to a stud (not shown) fixedly mounted on the head stock 70. The spring 98 serves normally to maintain the master cam 87 in operative engagement with the follower roller 94. -It will be readily apparent that rotary motion of the shaft 82 will be transmitted through the universal coupling 84, the shaft 85,- the universal coupling 86 to rotate the master cam 87 and the head stock spindle 73. The master cam 87 will impart a rocking motion to the head stock 70 and the rotation of the spindle 7-3 will impart a rotary motion to the work piece to be ground.

A driving mechanism is provided for imparting a rotary motion to the master earns 83 and 87and to the head stock spindle 73. This mechanism comprises a motor 100 mounted on the upper surface of the housing 66. The motor is provided with a driving pulley 101-which is connected by a V-belt 102 with a pulley 103 which is rotatably supported onthe left hand end of the trun- 1 nion 63. The pulley 103 is connected by multiple V-belts 104 with a multiple V-groove pulley 105 which is mounted on the left hand end of the shaft 81 (Fig. 3). The motor 100 is supported "on a pivotally mounted motor platen 106 (Fig. 4) which is pivotedat one end by a stud 107 carried by the housing .66. An adjusting screw 108 located adjacent to the other end of the platen 106 serves to facilitateadjusting .the motor platen.106 so asto tension the driving belt 102 as desired.

This improved machine is particularly adapted for grinding a convex surface on work pieces such as a jet motor blade 110 (Fig. 10). This blade may comprise a central portion having a convex surface 113 to be ground which is formed integral with block-like end portions 111 and 112 which are required for mounting the blade Within the jet motor. The convex surface 113 to be ground is straight line faired, being generated by movement of a straight line with ends moving along 'two curved paths of different and varying relative radii or radio distances from a given axis and the varying relative instance rates. If the surface is thus regarded as being made up of straight lines, the latter are thus never parallel to each other though portions of the surface, according to design or circumstances, may be directly cylindrical or frusto-conical where the two corresponding portions of the two paths through which the ends of the straight line move, those two portions are;equal or geometrically similar and: the rates of movement'therealong of the ends of the generating lines are the same.

Two or more'blades 110 may be ground at the same time by mounting theblades on a work holder v114 which is arranged'to be'supported on the work centers 76 and 68 respectively. As illustrated in Fig. 2 two blades 110 and 110a are mounted on diametrically opposite sides of the work holder .114. The endportions 111 and 112 of the blade'are provided with surfaces mating with surfaces onthe work holder 114 to locate the surface 113 tobe groundin the desired relationship with the axis OX of'rotation of the work holder I114. The blade 110 is clamped in position on the work holder 114 by work Rotationof. the work holder 114 on the work centers 76 and 68 respectively will present the convex surfaces 113 and 113a of the blades 110 and 110a respectivelyto the operative face of the grinding wheel.17.

As shown in Figs. 5 and 7 the portionof the blades 110 and 110a to be ground have been illustrated as. positioned on the work holder 114 in predetermined positions with respect to the axis OX. In Fig. 6 the shape of the blades 110 and 110a at the left hand end thereof is illustrated andin Fig. 8'the shape of the blades at the right hand end thereof is shown.

The master cams 83 and 87 are generated and shaped so as to impartthe desired and predetermined rocking movement to the head stock 70 and the foot stock .67 so that during a'rotary motion of the workholder 114 while supported on the work centers 76 and 68 respectively, the headstock 70 and foot stock 67 will be located about a commonraxis so;.as topresent-thefaces1113 and 11311 to be ground to the .operativejface of the grinding wheel 17 which will grind the convex face to a desired and predetermined shape.

Theoperationof. this machine willbe readily apparent from the foregoing disclosure. A pair of work pieces 110 and 110a are mounted in position on a work holder 114 which is then placed in position on the work centers 76 and 68 respectively. The grinding wheel motor-18 andthework driving motor, 100 arethen started. The

.feed mechanism is then actuated to advance the wheel =mined= extent-after-which the grinding wheel slide 15 and the grinding whe'el17-zare retracted to=a rearward or inoperative position.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiments above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a cam grinding machine having a base, a transversely movable wheel slide thereon, a rotatable grinding wheel on said slide, a longitudinallymovable table on said base, a headstock pivotally mounted on said table including a rotatable spindle having a work center, a footstock pivotally mounted on said table having a work center, said headstock and footstock being pivoted about a fixed horizontal common axis, means including a pair of independent synchronously rotated master cams including a master cam on said spindle and a master cam axially aligned with the footstock center, a pair of spaced followers arranged to engage said master cams independently to oscillate the headstock and footstock, and a driving mechanism synchronously to rotate said spindle and master cams to rotate a work piece and independently to oscillate the headstock and footstock so as to generate a cam contour on a work piece being ground differing from end to end.

2. In a cam grinding machine, as claimed in claim 1, in combination with the parts and features therein specified in which one of the master cams is mounted on the headstock spindle and the other master cam is rotatably mounted on an arm which is fixed relative to the footstock in axial alignment with the footstock center, a rotatable shaft, arranged parallel to the axis of the grinding wheel to support said follower rollers, yieldable means to maintain said master cams in operative engagement with said followers, and means including a motor operatively connected synchronously to rotate the headstock spindle and master cams to impart an independent oscillation to the headstock and footstock so as to generate a predetermined cam contour on a work piece.

3. In a cam grinding machine having a base, a transversely movable wheel slide thereon, a rotatable grinding wheel on said slide, a longitudinally movable work table on said base, a headstock pivotally mounted on said table having a rotatable spindle, a footstock pivotally mounted on said table, said headstock and footstock being pivoted about a common axis parallel to the axis of the grinding wheel, a work center on said spindle and on said footstock, a rotatable shaft on an arm which is fixedly mounted relative to said footstock in axial alignment with said footstock center, a pair of spaced master cams on said spindle and shaft respectively, a pair of spaced rotatable follower rollers in operative engagement with said master cams, and a driving mechanism synchonously to rotate said spindle and shaft so as to impart a simultaneously independent oscillation to said headstock and footstock to generate a predetermined cam contour on a work piece.

4. In a cam grinding machine, as claimed in claim 3, in combination with the parts and features therein specified in which the driving mechanism consists of a motor, driving connections between the motor and said shaft, and universal driving connections between the said shaft and said spindle so as to impart simultaneous independent oscillation to said headstock and said footstock.

5. In a cam grinding machine having a base, a transversely movable wheel slide thereon, a rotatable grinding wheel on said slide, a longitudinally movable work table on said base, a wheel feeding mechanism to feed said slide toward and from said table, a pivotally mounted rock bar on said table, a footstock thereon, a second pivotally mounted rock bar, said rock bars being arranged to pivot about a common axis, a headstock spindle rotatably supported on said rock bar, work supporting centers on the spindle and footstock to support a work piece to the ground, means including a motor operatively connected to rotate said headstock spindle to impart a rotary motion to the work piece being ground, a pair of synchrously rotated cams one on the headstock spindle and the other on an arm fixedly mounted relative to the footstock, and independent rotatable followers in operative engagement with said cams to impart an independent simultaneous oscillation to said spindle and footstock so as to generate a cam contour on a Work piece diifering from end to end.

6. In a grinding machine having a base, a transversely movable wheel slide thereon, a rotatable grinding wheel on said slide, a longitudinally movable work table on said base, a feeding mechanism to feed the grinding wheel transversely toward and from the work table, a headstock pivotally mounted on said table, a rotatable spindle on said headstock having a work supporting center, a footstock pivotally mounted on said table having a work supporting center, the pivotal axis of the footstock being axially aligned with the pivotal axis of the headstock, a pair of synchronously rotatable master cams one on the headstock spindle and the other on an arm fixedly mounted relative to the footstock, and independent rotatable followers in operative engagement with said cams independently to oscillate the headstock and footstock to generate a cam contour on the work piece being ground.

References Cited in the file of this patent UNITED STATES PATENTS 481,259 Feicker Aug. 23, 1892 1,474,171 Schumann Nov. 13, 1923 2,527,285 Whitehead Oct. 24, 1950 2,599,987 Green June 10, 1952 2,660,836 Green Dec. 1, 1953 FOREIGN PATENTS 679,272 Great Britain Sept. 17, 1952 

